(a) Field of the Invention
The present invention relates to an optical information recording medium having a recording layer containing a specific double salt or a recording layer containing said specific double salt and an organic dye. In more detail, the present invention relates to an optical information recording medium for use in a method of directly recording and regenerating information with a laser beam.
(b) Description of the Prior Art
A method of recording and regenerating information by radiating a laser beam on a rotating disk-shaped optical information recording medium has hitherto been known. As the optical information recording medium for use in this method there has been proposed the one which comprises providing on, a substrate, a thin layer of a low melting metal or a mixed thin layer of this metal and a dielectric substance. However, the optical information recording medium of this sort is disadvantageous in respect of inferior preservability, low resolving power, low recording density, high production cost and the like. In recent years, further, it has been proposed to use an organic dye thin film, whose physical properties are changeable upon exposure to a relatively long wavelength light such as a semiconductor laser beam, for a recording layer. This organic dye thin film surely can eliminate the above defects, but involves the problems that the organic dye, which has absorptivity on the long wavelength side, is generally inferior in stability against heat and light when used singly, and the like. In view of this, it has been proposed to incorporate a metal complex in an organic thin film recording layer. However, the fact is that only the mixture of the organic dye and the metal complex as mentioned above can not attain sufficient recording and regenerating characteristics.